In recent years, the application of so-called optical interconnection has become wide-spread as a technology for transmitting signals at high speed within a system device, between devices, or between optical modules. Here, optical interconnection refers to a technology in which optical components are handled as if they are electronic components, and are mounted on motherboards, circuit boards, and the like used in personal computers, vehicles, optical transceivers, and the like.
An optical module used in optical interconnection such as this serves various purposes, such as internal connection for media converters and switching hubs, and in-device and inter-device component connection for optical transceivers, medical equipment, testing devices, video systems, high-speed computer clusters, and the like.
As an optical component applied to this type of optical module, there is an increasing demand for a lens array in which a plurality of lenses having a small diameter are disposed in an array, as a compactly structured component effective for actualizing multichannel optical communication.
Here, the lens array is conventionally configured such that a photoelectric conversion device including a plurality of light-emitting elements (such as a vertical cavity surface emitting laser [VCSEL]) can be attached thereto, and a plurality of optical fibers serving as an optical transmission body can be attached thereto.
In a state in which the lens array is disposed between the photoelectric conversion device and the plurality of optical fibers in this way, the lens array optically couples light emitted from each light-emitting element of the photoelectric conversion device with an end face of each optical fiber. As a result, multichannel optical transmission can be performed.
In addition, among photoelectric conversion devices, some include a monitoring light-receiving element for monitoring light (particularly intensity or amount of light) emitted from the light-emitting elements to stabilize the output characteristics of the light-emitting elements. A lens array supporting such photoelectric conversion devices is configured to reflect some of the light emitted from the light-emitting elements towards the monitoring light-receiving element as monitor light.
As a lens array that includes a reflection function for generating the monitor light such as this, the inventors of the present invention have made proposals in the past, such as that in Patent Literature 1.